The study says the number of children under five is forecast to decline by more than 40% Earth will be home to 8.8 billion people in 2100, two billion fewer than current UN projections, according to a major study published today that foresees new global power alignments shaped by declining fertility rates and greying populations. By century's end, 183 of 195 countries, barring an influx of immigrants, will have fallen below the replacement threshold needed to maintain population levels, an international team of researchers reported in The Lancet. More than 20 countries, including...